Restarting the adapted binaural system

Hafter, Ervin R.; Buell, Thomas N.

doi:10.1121/1.399730

Cited by 76 publications

(92 citation statements)

References 3 publications

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“…This finding extends the conclusion of Hafter and Buell (16) on the recovery from binaural adaptation in acoustic hearing by inserting a trigger (a temporal gap or a brief sound) into a pulse train. They attributed the recovery effect to the spectral changes induced by the trigger.…”

Section: Discussionsupporting

confidence: 75%

“…Binaural adaptation has such a strong effect on ITD perception at higher pulse rates that the onset of a sound receives maximum perceptual weight, whereas the ongoing signal contributes little (14,15). Going one step further, studies with NH listeners have shown that introducing a change in the ongoing signal (a trigger) causes a recovery from binaural adaptation (15,16). As a consequence, the portion of the signal after the trigger becomes more important and this results in improved ITD sensitivity.…”

mentioning

confidence: 99%

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Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

Laback

Majdak

2008

Proc. Natl. Acad. Sci. U.S.A.

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Interaural time difference (ITD) arises whenever a sound outside of the median plane arrives at the two ears. There is evidence that ITD in the rapidly varying fine structure of a sound is most important for sound localization and for understanding speech in noise. Cochlear implants (CIs), neural prosthetic devices that restore hearing in the profoundly deaf, are increasingly implanted to both ears to provide implantees with the advantages of binaural hearing. CI listeners have been shown to be sensitive to fine structure ITD at low pulse rates, but their sensitivity declines at higher pulse rates that are required for speech coding. We hypothesize that this limitation in electric stimulation is at least partially due to binaural adaptation associated with periodic stimulation. Here, we show that introducing binaurally synchronized jitter in the stimulation timing causes large improvements in ITD sensitivity at higher pulse rates. Our experimental results demonstrate that a purely temporal trigger can cause recovery from binaural adaptation. Thus, binaurally jittered stimulation may improve several aspects of binaural hearing in bilateral recipients of neural auditory prostheses.binaural adaptation ͉ cochlear implant ͉ fine structure ͉ lateralization ͉ localization I nteraural time difference (ITD) arises whenever a sound source outside the median plane arrives at the two ears and provides important information on the sound's lateral position. ITD occurs both in the rapidly varying fine structure and in the slowly varying envelope of the signal. There is evidence that ITD in the fine structure of a sound is most important for sound localization (1, 2) and for understanding speech in noise (3, 4). Listeners bilaterally supplied with cochlear implants (CIs) have been shown to be sensitive to fine structure ITD, but their sensitivity disappears at a pulse rate of a few hundred pulses per second (5-8). This is in contrast to normal hearing (NH) listeners, who are sensitive to ITD in the fine structure up to much higher frequencies (9, 10). The CI listeners' limitation in the ability to process fine structure ITD information at higher rates is disadvantageous with respect to speech coding where such high rates are required.In this study, we present a method of electric stimulation that improves CI listeners' sensitivity to fine structure ITD at higher pulse rates. The method is based on previous findings on the limitation in ITD perception at higher modulation rates in NH listeners.In studies with NH listeners, it has been observed that the sensitivity to ITD information degrades with increasing modulation rate of a high-frequency carrier signal (11,12). By using filtered pulse trains, it was shown (11, 13) that, as pulse rate increases, increasing the stimulus duration yields a smaller improvement of ITD sensitivity than would be expected from a model based on optimum integration of ITD information across time (11). This effect has been referred to as binaural adaptation. Binaural adaptation has such a strong effect...

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Section: Discussionsupporting

confidence: 75%

mentioning

confidence: 99%

Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

Laback

Majdak

2008

Proc. Natl. Acad. Sci. U.S.A.

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“…(Hafter and Buell, 1990;Laback and Majdak, 2008;Goupell et al, 2009b;Brown and Stecker, 2011). Such a change partially restores sensitivity to ITDs and ILDs at higher pulse rates.…”

Section: Introductionmentioning

confidence: 89%

“…GN has more extensive envelope modulations and therefore will suffer less from binaural adaptation because of restarting (Hafter and Buell, 1990). The envelopes of the stimuli from experiment 1 were sampled with band-limited pulses that encoded the instantaneous amplitude at regular time intervals.…”

Section: Experiments 2: Effects Of Repetition Rate On Binaural Pementioning

confidence: 99%

“…The GN-LFN difference could be partially due to "binaural adaptation" (Hafter and Buell, 1990). Binaural adaptation is the phenomenon whereby sensitivity to interaural time differences (ITDs) and interaural level differences (ILDs) in constant-amplitude pulse trains decreases with increasing pulse rate Stecker and Hafter, 2002;Brown and Stecker, 2010;Stecker and Brown, 2010).…”

Section: Introductionmentioning

confidence: 99%

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The role of envelope statistics in detecting changes in interaural correlation

Goupell

2012

The Journal of the Acoustical Society of America

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The role of envelope statistics in binaural masking-level differences (BMLDs) and correlation change detection was investigated in normal-hearing listeners. Thresholds and just-noticeable differences (JNDs) were measured for different bandwidths and center frequencies (500, 2000, 4000, and 8000 Hz) using Gaussian noises (GNs) and low-fluctuation noises (LFNs). At a 500-Hz center frequency, GN NoSo thresholds were higher than, NoSp thresholds were lower than, and correlation change detection JNDs were the same as LFN thresholds and JNDs. At higher center frequencies, GN NoSp thresholds were the same or higher than LFN thresholds and GN correlation change detection JNDs were much smaller than LFN JNDs. Using a pulsed sine vocoder, a second experiment was performed to investigate if binaural adaptation might contribute to the difference in GN and LFN detection. There was no effect of pulse rate, thus providing no clear evidence that binaural adaptation plays a role in these tasks. Both a cross-correlation model and a model that utilized the fluctuations in the interaural differences could explain a majority of the variance in the LFN correlation change JNDs.

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Spatial Hearing and Perceiving Sources

Darwin¹

Auditory Perception of Sound Sources

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Restarting the adapted binaural system

Cited by 76 publications

References 3 publications

Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

Binaural jitter improves interaural time-difference sensitivity of cochlear implantees at high pulse rates

The role of envelope statistics in detecting changes in interaural correlation

Spatial Hearing and Perceiving Sources

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